🔌 Lost + Found RCWL-0516 Radar Motion Sensor Driver

This driver provides a simple, interrupt-driven interface for the RCWL-0516 microwave Doppler radar motion sensor module on the Raspberry Pi Pico 2 (RP2350).

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🎛️ Hardware Description & Specifications

The RCWL-0516 uses Doppler radar to detect moving objects. Unlike PIR (passive infrared) sensors, it is highly sensitive to motion and can detect movements through thin walls, plastic, wood, and glass.

📐 Sensor Characteristics & Tentative Specifications

• Default Output Trigger Timeout: ~2 seconds. The sensor output goes HIGH for 2s upon detecting motion, then drops LOW (enters idle state).
• Detection Distance/Range: Typically 5 to 7 meters (up to 9m maximum depending on mounting and environment).
• Detection Angle: 360 degrees (omnidirectional sensing). Sensitivity is slightly higher facing the front component side of the PCB, but it detects motion in all directions.
• RF Penetration: Can penetrate non-metallic barriers. Avoid metal enclosures, which block microwave radar signals completely.

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🔌 Wiring Diagram (Pico 2)

Sensor Pin	Pico 2 GPIO Pin	Pico 2 Physical Pin	Notes
VIN	VBUS	Pin 40	Power input (5V).
GND	GND	Pin 38 (or any GND)	Common ground reference.
OUT	GP15	Pin 20	Digital output (3.3V logic level, active-HIGH).
3V3	Disconnected	—	Unused 3.3V output from onboard regulator.

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🚀 Usage Example

Configure your application to route GPIO interrupts to the driver handler.

#include "pico/stdlib.h"
#include "lf_rcwl0516.h"
#include <stdio.h>

#define SENSOR_PIN 15
static lf_rcwl0516_t radar;

void gpio_callback(uint gpio, uint32_t events) {
    if (gpio == SENSOR_PIN) {
        lf_rcwl0516_irq_handler(&radar);
    }
}

int main() {
    stdio_init_all();
    
    lf_rcwl0516_init(&radar, SENSOR_PIN);
    
    gpio_set_irq_enabled_with_callback(
        SENSOR_PIN,
        GPIO_IRQ_EDGE_RISE | GPIO_IRQ_EDGE_FALL,
        true,
        &gpio_callback
    );
    
    while (true) {
        bool motion = false;
        if (lf_rcwl0516_check_and_clear_changed(&radar, &motion)) {
            printf("[EVENT] Sensor state: %s\n", motion ? "MOTION DETECTED" : "CLEAR/IDLE");
        }
        __wfi();
    }
}